The present invention relates to the field of parking aids for automobile vehicles, and more particularly, entirely automatic parking aid systems for performing parking maneuvers of the slot type.
Carrying out slot-type maneuvers is often a source of stress, caused by the difficulty in carrying out these maneuvers, which can be associated with the appreciation of various parameters in the performance of these maneuvers which are notably, the appropriateness of the parking space to the length of the vehicle, the initial positioning of the vehicle, the sequencing of the parking maneuvers, etc., which may also lead to risks of degradation of the vehicle being maneuvered and of the vehicles adjacent to the parking space targeted.
In addition, the temporary blocking of the road traffic is also a source of stress due to the annoyance caused to the other car drivers.
Thus, semi-automatic devices for assisting maneuvers for the slot parking of vehicles have been developed with the aim of facilitating this operation. These devices are based on methods for planning the path to be followed which can be divided into several groups:                Methods based on the use of reference functions. For example, these may use the Lyapunov function for stabilizing the vehicle onto a line corresponding to the parking space, then onto a precise point of the parking space. They may also use sinusoidal functions with various gains so as to converge toward a path to be followed for entering into the parking space. For these methods, the behavior of the vehicle is essentially dependant on the parameters chosen and the drawback of these methods is the risk of not converging toward a path to be followed that may be performed by the vehicle within the space available.        Methods based on fuzzy logic based on learning human behavior. These methods do not require planning of a path to be followed but they are limited to the experience of human experts and are difficult to generalize.        Methods for planning in two steps: firstly, a collisionless path is created without taking into account the constraints of the vehicle, then this path is continually subdivided into points until all the points may be connected by paths that are feasible for the vehicle.        Geometrical methods which are based on arcs of circles that are feasible for the vehicle without collision and which bring the vehicle into its parking space. The paths to be followed resulting from these methods may be simply expressed using geometrical equations.        
From the document US2009/0260907, an automation of the steering is for example known for maneuvering for entry into a parking slot in one or two maneuvers depending on the length of the space available with respect to the dimensions of the vehicle to be parked. It turns out, as a consequence, that this minimum length of the parking space is important, which gives rise to a severe limitation on the free parking space and can, in the case where the space is judged to be too small, lead to the frustration of the driver seeing the system refuse such a parking space which he/she him/herself thinks has sufficient room, albeit with the application of several maneuvers. The driver is then obliged to carry out these annoying parking maneuvers him/herself which are indeed those that he/she would have preferred not to have to do.
Moreover, these parking strategies in one or two maneuvers require that the vehicle is correctly positioned for the start of the maneuver, in other words that it is parallel to the parking space, and at a distance that is well defined with respect to the geometrical calculations for performing the maneuver (arcs of a circle corresponding to the maximum steering lock of the vehicle).
One of the aims of the invention is thus to provide a parking strategy allowing a vehicle to be guided into a free space whenever the free parking slot allows the car to be contained, taking into account the maneuvers needed to bring the vehicle into said space.
Another aim of the invention is to inform the driver of the parking possibilities when a free space is located.
Another aim of the invention is to provide an entirely automatic maneuver, where the driver does not intervene in the parking maneuvers, the vehicle potentially even being unoccupied during the maneuvers.